ReSpeaker 4-Mic Linear Array Kit for Raspberry Pi

Seeed’s ReSpeaker 4-Mic Linear Array Kit is
an extension board, aka HAT designed for Raspberry Pi. It's a linear microphone array
kit, comes with four microphones and
designed for AI and voice applications. That
means you can build a more powerful and
flexible voice product with Raspberry Pi
which can integrate Amazon Alexa Voice
Service, Google Assistant, and so on.

ReSpeaker 4-Mic Linear Array Kit for
Raspberry Pi consists of two boards, one is
voice accessory HAT, another is four
microphones linear array.

To make this kit work with alexa or dueros, you need to open a web site to get the authorization. So you need to use VNC Viewer to log in your amazon or baidu account. So please make sure you have open the VNC service of your raspberry.

Or you can just consider plan B.

Plan B

If you are tired of all above, you can just use a HDMI Monitor and plug the USB Keyboard and USB mouse in to your raspberry, it works too, simple and easy.

Step 1. Install seeed-voicecard

Get the seeed voice card source code. and install all linux kernel drivers.

To get the authorization, you need to open the Internet Brownser to log in your Amazon or Baidu ID, so you need to use VNC Viewer or just do it via monitor and keyboard. The same as ssh, you need the IP of your raspberry to log in VNC.

To do this part, you also need to get the authorization of Alexa or Baidu at first.

As you may see, the demos above trigger the Alexa or Dueros by tapping the Enter key. What if you want to wake up the Alexa by voice?
Well, you can use snowboy. And you only need simple steps to make that happen.

Then you need to edit the rules.
As the system start, when the card "seeed8micvoicec" is detected, the PULSE_PROFILE_SET variable will be set in the udev database, and PulseAudio will be forced to use seeed-voicecard.conf.
At first, please use the following command to check the rule.

1

sudo nano /lib/udev/rules.d/90-pulseaudio.rules

Then add the following lines at about line 87(behind the setting for some laptops and before the line GOTO="pulseaudio_end")

Q1: There are only 4 Mic in the Mic Array, how could it be 8 channels?

A1: There are 2 AC108 in this array, and each AC108 chip has 4 channel output. So it comes a total of 8 channels here, 4 of which are for the microphone, two channels for the playback and the the rest 2 channels are not used.